AVFs and AVMs – symptoms of rare spinal cord injury to look out for

The Spinal Injury team at Bolt Burdon Kemp have represented clients with spinal cord injuries who have come by their injury in very different ways. No two spinal cord injuries are the same – from the cause of the injury itself to the impact on the person, every individual and their journey is unique. Some suffer trauma, for example a road traffic accident or an accident at work. Others develop medical conditions such as cauda equina syndrome which, if left undiagnosed, can result in irreversible harm. Some of these conditions are rare, such as the main focus of this blog –  Arteriovenous Fistulas (AVFs) and Arteriovenous Malformations (AVMs).

Focusing specifically on AVFs and AVMs impacting the spine, this blog highlights the key causes, symptoms, methods of diagnosis and treatment, and information on when to seek medical advice.

What are AVFs and AVMs?

AVFs and AVMs are rare vascular abnormalities where there is an abnormal connection between an artery – which carries blood away from the heart, and a vein – which carries blood towards the heart.

AVFs are found on the surface or covering of the brain or spinal cord, whereas AVMs are found within the tissue of the brain or spinal cord.

When this abnormality is present, it puts pressure on the system around the brain or spinal cord, depending where the AVF or AVM is situated.

Causes

People can be born with AVFs and AVMs or they can arise later in life.

A dural AVF/AVM – an abnormality in the lining of the brain or spinal cord – is an example of an acquired AVF which can be caused by infection or a traumatic injury. According to a study, spinal dural AVFs are more common in middle-aged men.

AVFs can also develop spontaneously without any specific cause.

Symptoms

Symptoms of an AVF or AVM will depend on where it is located in the body.

For example, an AVF in the lungs can result in coughing up blood.

An AVF in or around the spinal cord can result in pressure on the spinal cord (compression) which results in symptoms, which depending on the level of the compression can include loss of sensation, weakness in the limbs and bladder, bowel and sexual function issues.

In our experience, dural AVFs of the spinal cord in particular present in an insidious way and can cause significant and progressive decline in sensory and motor function.

Diagnosis and treatment

Considering the symptoms an AVF causes and the long-term impact if not treated, it is important to identify and diagnose an AVF as soon as possible.

For example, if a spinal AVF goes untreated, it could result in deterioration of symptoms and ultimately end in paralysis, so the consequences are significant.

If an AVF is suspected, the first investigation that a medical professional should arrange is an angiogram. An angiogram is a test in which dye is injected into the blood vessels so that images can be taken to identify an AVF. This is performed by a neuroradiologist.

Once an AVF has been identified it can be treated. Generally, it is considered that the earlier the diagnosis and treatment, the better the outcome.

If someone with a spinal AVF is experiencing worsening symptoms as above, it can cause blood clots and irreversible spinal cord injury. A delay in diagnosis and treatment could also result in haemorrhaging.

The aim of treatment is to prevent further deterioration of symptoms or reverse the damage caused by the AVF/AVM and improve quality of life.

The treatment options for an AVF/AVM will depend on the severity of the symptoms and where the AVF is.

For example, a spinal AVF can often be treated with a procedure which involves passing a catheter through the blood vessels and into the fistula, then sealing off the fistula to prevent its ongoing impact.

Alternatively, surgery may be required to remove the malformation entirely to restore blood flow.

When you should seek professional medical advice

The spinal cord is fragile and can affect the function of other parts of your body if impacted. Elongated compression of the spinal cord can result in ongoing and irreversible symptoms, which means that early identification, diagnosis and treatment of an AVF/AVM of the spinal cord is critical.

Symptoms and signs of cord compression are:

• Radicular pain
• Limb weakness
• Difficulty walking
• Sensory loss or abnormal sensation
• Bladder and/or bowel dysfunction

If you think you are suffering with the above symptoms, or if in any doubt, always seek medical attention. A medical professional can advise on next steps for identification, diagnosis and treatment of the potential cause of your symptoms.

For more information on symptoms of potential cord compression and when to seek medical advice, click here.

When you should seek professional legal advice

Spinal AVFs are very rare and there are only 5 – 10 new cases per million each year. This means many medical professionals will not have come across a patient with one before. However this is not an excuse when an AVF is missed.

As detailed above, patients with AVFs or AVMs will present with unusual neurological symptoms.

A medical professional should recognise investigations are warranted, consider common and rare conditions and should order timely scanning.

Failure to act in a timely manner which results in a worse outcome can give rise to a medical negligence claim.